Re: [PATCH] rebase: learn --discard subcommand

[Martin von Zweigbergk <martin.von.zweigbergk@gmail.com>]

On Sat, 28 May 2011, Junio C Hamano wrote:

> Martin von Zweigbergk <martin.von.zweigbergk@gmail.com> writes:
> 
> > ... I think Junio then
> > hinted that he sometimes wished that he could abort rebase without
> > moving to anywhere else at all, which is what this patch implements.
> 
> I am not opposed to this particular patch, but thinking about a bigger
> picture, I am not sure if we want to solve it this way.
> 
> We have multiple "sequence" operations that want to do things in multiple
> steps, each of which can stop and give control back to the user, while
> leaving some information in the .git directory for it to know where it was
> when resuming. I think "am" knows about what "rebase" does (and
> vice-versa) so it can detect an attempt to run it while "rebase" is in
> still progress and refuse to continue to limit the damage, but if we have
> N such "sequence" commands that want to refrain from interfering with each
> other, and want to offer an advice to abort the in-progress operation
> initiated by other commands, that would mean we would need N * N pieces of
> logic to detect other's in-limbo state and offer advices, which would not
> scale.

Makes sense. I think someone once suggested to have a .git/inprogress
directory that would contain some basic information that could be used
to diagnose in a generic way what operation might be in progress.

> A user who is given back the control from a "sequence" operation may be
> confused either (1) immediately after such an event (often some sort of
> merge conflict) or (2) much later after first abandoning the working tree
> altogether and taking a walk and then coming back to continue working
> while forgetting what he was doing. Such a user may want to say "I know I
> am in a strange state, give me a state that I can work from, at this point
> I do not care about continuing what I was originally doing". The user may
> probably not know if "git rebase" was in progress or "git cherry-pick"
> was.

Maybe the recent patch [1] about adding information to git status
about any ongoing operation would help. I'm not sure, but I think I
would personally be a bit hesitant to cancel the current sequence
operation without first checking what it was. OTOH, if I don't even
remember starting a rebase operation, maybe knowing whether it was a
rebase or an am operation might not help much. But if the message from
git status would actually say something like "rebase in progress:
[2/3] War on nbsp: a bit of retreat", then that might help more in
making a decision to cancel or not.


 [1] http://thread.gmane.org/gmane.comp.version-control.git/172919